[PATCH v3 05/14] s390/pkey: Remove redundant rcu_read_lock/unlock() in spin_lock
From: pengdonglin <hidden>
Date: 2025-09-16 04:48:49
Also in:
cgroups, intel-gfx, linux-acpi, linux-fsdevel, linux-nfs, linux-rt-devel, linux-s390, linux-security-module, linux-wireless, lkml
Subsystem:
s390 architecture, s390 zcrypt and pkey driver and ap bus, the rest · Maintainers:
Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Harald Freudenberger, Holger Dengler, Linus Torvalds
From: pengdonglin <redacted>
Since commit a8bb74acd8efe ("rcu: Consolidate RCU-sched update-side function definitions")
there is no difference between rcu_read_lock(), rcu_read_lock_bh() and
rcu_read_lock_sched() in terms of RCU read section and the relevant grace
period. That means that spin_lock(), which implies rcu_read_lock_sched(),
also implies rcu_read_lock().
There is no need no explicitly start a RCU read section if one has already
been started implicitly by spin_lock().
Simplify the code and remove the inner rcu_read_lock() invocation.
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Holger Dengler <dengler@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: pengdonglin <redacted>
Signed-off-by: pengdonglin <redacted>
---
drivers/s390/crypto/pkey_base.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/drivers/s390/crypto/pkey_base.c b/drivers/s390/crypto/pkey_base.c
index b15741461a63..4c4a9feecccc 100644
--- a/drivers/s390/crypto/pkey_base.c
+++ b/drivers/s390/crypto/pkey_base.c@@ -48,16 +48,13 @@ int pkey_handler_register(struct pkey_handler *handler) spin_lock(&handler_list_write_lock); - rcu_read_lock(); list_for_each_entry_rcu(h, &handler_list, list) { if (h == handler) { - rcu_read_unlock(); spin_unlock(&handler_list_write_lock); module_put(handler->module); return -EEXIST; } } - rcu_read_unlock(); list_add_rcu(&handler->list, &handler_list); spin_unlock(&handler_list_write_lock);
--
2.34.1